probe - Google Search
Looks like people are getting 375 to 400 watt hours per mile, not great but then again you are starting out with a 2,800 pound car that got 25-28mpg as a gas car, right?
Improve it by putting narrower and lower rolling resistance tires on it, smooth out the underside, make it lighter, and most of all, put lithium batteries in it as people seem to see an improvement of around 40% or even greater with lithium batteries.